"Another year, they tossed everybody into a landscape filled with nothing but boulders and scruffy bushes. I particularly hated that year. Many contestants were bitten by venomous snakes or went insane from thirst."
-Katniss talking about the 63d Games in The Hunger Games
Its known that his odds of winning were 5 - 1. Its also known that he didn't volunteer. He was mentored by Velorum Lathmore.
Its known that he allied with the other careers, and he was the youngest out of the pack. He acted tough, even though he was very scared to be in the arena. He faked this pretty well, acting strong and tough, and killing a fair amount of tributes in his respective Games.
Katniss mentioned in The Hunger Games that she remembered a Game from when she was younger where the tributes were tossed into a landscape filled with sand, boulders and scruffy bushes. Many of the tributes were either bitten by poisonous snakes, or went insane from thirst. One day, a tribute hid in the sand and bludgeoned a career to death with a rock, but this person quickly killed since the person winning this year was a career instead of a regular tribute.
This year was probably it, since its the only year thats left of a Hunger Games she remembered that hasn't really been mentioned before.